Process for preparing inhibited non-pregelatinized granular starches

ABSTRACT

An inhibited non-pregelatinized granular starch suitable for use as a food ingredient in substitution for a chemically modified starch may be prepared by heating a non-pregelatinized granular starch in an alcoholic medium in the presence of a base and/or a salt. Steam treatment may be used to enhance the extent of inhibition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional application Nos.61/647,146, filed May 15, 2012, and 61/810,545, filed Apr. 10, 2013,each of which is incorporated herein by reference in its entirety forall purposes.

FIELD OF THE INVENTION

The invention relates to the production of inhibited non-pregelatinizedgranular starches which are useful as ingredients in food compositions.

BACKGROUND OF THE RELATED ART

A recent trend in the food industry has been growing consumer demand forso-called “clean-labelled” or non-chemically modified ingredients. Inapplications where it is desired to thicken a food product such as asoup or sauce which is to be subjected to severe acid and/or heat and/orshear conditions during either its processing or its end use, chemicallymodified starches have traditionally been used since such starches areremarkably tolerant of such extreme conditions. These chemicallymodified starches are produced by various crosslinking techniqueswherein a chemical reagent is used to form crosslinks in the starch andthereby alter its viscosity and stability characteristics at elevatedtemperatures. However, it would be desirable to develop replacements forsuch chemically modified starches which exhibit similar performance andyet would not be regarded or classified as chemically modified forlabelling purposes.

SUMMARY OF THE INVENTION

The invention provides a method for making an inhibitednon-pregelatinized granular starch, wherein the method comprises heatinga non-pregelatinized granular starch in an alcoholic medium in thepresence of at least one treatment agent selected from the groupconsisting of bases and salts at a temperature of at least 35° C.

In another aspect, the invention provides a method for making aninhibited non-pregelatinized granular starch, wherein the methodcomprises:

-   -   a) heating a non-pregelatinized granular starch in an alcoholic        medium in the presence of a base at a temperature of at least        35° C.;    -   b) neutralizing the base with an acid;    -   c) separating the inhibited non-pregelatinized granular starch        from the alcoholic medium; and    -   d) removing alcohol solvent from the inhibited        non-pregelatinized granular starch by heating.

The alcoholic medium may be comprised of a C1-C4 alcohol (e.g.,ethanol). In another embodiment, the alcoholic medium is comprised of 0to 20 weight percent water. In one embodiment, the alcoholic medium isbasic. In another embodiment, the alcoholic medium is neutral. Thetemperature in step a) may, in one embodiment, be at least 120° C. Theheating in step a) may, for example, be carried out for a period of timeof from 5 minutes to 20 hours. The treatment agent may, for example, bea base selected from the group consisting of alkali metal hydroxides,alkali metal carbonates (in particular, sodium carbonate), alkali metalphosphates, ammonium phosphates, alkaline earth carbonates and alkalineearth hydroxides. The treatment agent may include a polycarboxylic acidsalt. The polycarboxylic acid salt may, for example, be a sodium orpotassium salt of a polycarboxylic acid. The treatment agent in oneembodiment includes one or more sodium salts of citric acid. Thetreatment agent may be present in an amount of not more than 10 weightpercent based on the weight of the non-pregelatinized granular starchand/or may be present in an amount of at least 0.2 weight percent basedon the weight of the non-pregelatinized granular starch. The method maycomprise an additional step of removing alcohol solvent from theinhibited non-pregelatinized granular starch. The method may comprise anadditional step of separating the inhibited non-pregelatinized granularstarch from the alcoholic medium and heating the separated inhibitednon-pregelatinized granular starch. The heating of the separatedinhibited non-pregelatinized granular starch, in one embodiment, isconducted at a temperature of at least 120° C. The method may comprisean additional step of treating the inhibited non-pregelatinized granularstarch with steam. The non-pregelatinized granular starch utilized as astarting material may, for example, be selected from the groupconsisting of corn starch, pea starch, potato starch, sweet potatostarch, banana starch, barley starch, wheat starch, rice starch, sagostarch, amaranth starch, tapioca starch, sorghum starch, waxy maizestarch, waxy pea starch, waxy wheat starch, waxy tapioca starch, waxyrice starch, waxy barley, waxy potato, waxy sorghum, starches having anamylose content of 40% or greater, and combinations thereof. Inparticular, the non-pregelatinized granular starch may be corn starch ora waxy starch. In one embodiment of the method, the non-pregelatinizedgranular starch is in the form of a slurry in the alcoholic medium andthe pH of the slurry is at least 6. In another embodiment, the at leastone treatment agent includes a base and the method comprises anadditional step of neutralizing the base in the inhibitednon-pregelatinized granular starch with an acid. The acid may, forexample, be selected from the group consisting of phosphorus-containingacids, carboxylic acids, uric acid and mixtures thereof. For instance,the acid may be selected from the group consisting of citric acid,oxalic acid, malic acid, lactic acid, acetic acid and mixtures thereof.The acid may be a polycarboxylic acid. After neutralization, a furtherstep of heating the inhibited non-pregelatinized granular starch in thealcoholic medium may be carried out. For example, the further heating ofthe inhibited non-pregelatinized granular starch in the alcoholic mediummay be carried out at a temperature of from about 120° C. to about 200°C.

In yet another aspect, the invention provides a method for making aninhibited non-pregelatinized granular starch, wherein the methodcomprises:

-   -   a) heating a slurry of a non-pregelatinized granular starch in        an aqueous ethanol medium in the presence of a base at a        temperature of 120° C. to 200° C.;    -   b) neutralizing the base with an acid;    -   c) separating the inhibited non-pregelatinized granular starch        from the aqueous ethanol medium; and    -   d) contacting the separated inhibited non-pregelatinized        granular starch with steam at a temperature of from 100° C. to        200° C. to remove ethanol.        Following step b) and prior to step c), the neutralized slurry        may be again heated, e.g., at a temperature of 120° C. to 200°        C.

Also provided by the present invention is a method for making aninhibited non-pregelatinized granular starch, wherein the methodcomprises:

-   -   a) heating a non-pregelatinized granular starch in an alcoholic        medium in the presence of a base at a temperature of at least        35° C.;    -   b) neutralizing the base with an acid to provide a neutralized        slurry;    -   c) heating the neutralized slurry at a temperature of at least        35° C.;    -   d) separating the inhibited non-pregelatinized granular starch        from the alcoholic medium; and    -   e) removing alcohol solvent from the inhibited        non-pregelatinized granular starch by heating.

Another aspect of the present invention provides a method for making aninhibited non-pregelatinized granular starch, wherein the methodcomprises:

-   -   a) heating a non-pregelatinized granular starch in an alcoholic        medium in the presence of a carboxylic acid salt at a        temperature of at least 35° C.;    -   b) separating the inhibited non-pregelatinized granular starch        from the alcoholic medium; and    -   c) removing alcohol solvent from the inhibited        non-pregelatinized granular starch by heating.

The alcoholic medium may be comprised of a C1-C4 alcohol, such asethanol. The alcoholic medium may comprise 0 to 20 weight percent water.In one embodiment, the temperature in step a) is at least 120° C. Thecarboxylic acid salt may, for example, be present in an amount of notmore than 10 weight percent based on the weight of thenon-pregelatinized granular starch. The carboxylic acid salt may, forexample, be present in an amount of at least 0.2 weight percent based onthe weight of the non-pregelatinized granular starch. In one embodiment,the heating of the separated inhibited non-pregelatinized granularstarch in step c) is conducted at a temperature of at least 120° C. Theaforementioned method may comprise a step of treating the inhibitednon-pregelatinized granular starch with steam. The non-pregelatinizedgranular starch may, for example, be selected from the group consistingof corn starch, pea starch, potato starch, sweet potato starch, bananastarch, barley starch, wheat starch, rice starch, sago starch, amaranthstarch, tapioca starch, sorghum starch, waxy maize starch, waxy peastarch, waxy wheat starch, waxy tapioca starch, waxy rice starch, waxybarley, waxy potato, waxy sorghum, starches having an amylose content of40% or greater, and combinations thereof. In particular embodiments, thenon-pregelatinized granular starch is corn starch or a waxy starch. Thenon-pregelatinized granular starch may be in the form of a slurry in thealcoholic medium and the pH of the slurry may be from 5 to 8, in certainembodiments of the invention. The heating in step a) may, for example,be carried out for a period of time of from 5 minutes to 20 hours. Theat least one carboxylic acid salt may include a polycarboxylic acidsalt, such as a sodium or potassium salt of a polycarboxylic acid. Inone aspect of the invention, the at least one carboxylic acid saltincludes one or more sodium salts of citric acid. The at least onecarboxylic acid salt may be formed in situ prior to step a) by combiningat least one carboxylic acid with at least one base.

Still another aspect of the invention provides inhibitednon-pregelatinized granular starches obtained in accordance with any ofthe above-mentioned methods.

The present invention thus enables the preparation of inhibited starcheswithout the use of hazardous chemicals, using only food gradeingredients. Additionally, no hazardous chemicals are produced duringsuch preparation. Starches produced in accordance with the invention canbe inhibited to levels comparable to highly chemically cross-linkedstarches and can be used in the same applications where chemicallymodified starches are conventionally used. For example, inhibitedstarches obtained in accordance with the methods of the invention can beutilized as alternatives or substitutes for chemically modified starcheswhere severe acid and/or heat and/or shear conditions exist or areapplied.

BRIEF DESCRIPTION OF THE FIGURES

The Figures are explained in more detail in the Examples.

FIG. 1 shows the Rapid Visco-Analyzer (RVA) profiles (Cookup) ofdifferent starch samples measured at a 5% concentration in a pH 6.5aqueous medium.

FIG. 2 shows micrographs of starch pastes after RVA at pH 6.5(magnification 200×).

FIG. 3 shows the RVA profiles (Cookup) of different starch samplesmeasured at a 5% concentration in a pH 3.5 aqueous medium.

FIG. 4 shows micrographs of starch pastes after RVA at pH 3.5(magnification 200×).

FIG. 5 shows micrographs of various starch pastes after retortsimulation.

FIG. 6 shows micrographs of various starch samples, some of which weretreated in accordance with the present invention.

FIG. 7 shows the RVA profiles (Cookup) of various starch samplesmeasured at a 5% concentration in a pH 6.5 aqueous medium.

FIGS. 8 and 9 show the RVA profiles of various starch samples, includingsamples prepared in accordance with the invention as well as achemically modified waxy starch with high cross-linking availablecommercially from Tate & Lyle.

FIGS. 10 and 11 show the RVA profiles of various starch samples measuredat 6.65% in a buffer having a pH of 3.5.

FIGS. 12-15 show micrographs of starch granules in various samples ofstarch paste after RVA and retort simulation.

FIGS. 16, 17 and 24 show the RVA profiles at different pHs of treatedstarch samples before and after desolventization.

FIGS. 18, 20 and 25 show micrographs of treated starch samples cooked in1% NaCl.

FIGS. 19, 21 and 26 show micrographs of treated starch samples cooked in1% NaCl and then sheared using a blender.

FIGS. 22, 23 and 27 show micrographs of treated starch samplesilluminated with polarized light.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term “inhibited starch” means a starch having thecharacteristics of a chemically crosslinked starch. Inhibited starchesmay vary with respect to their degree of inhibition, as characterized bytheir observed viscosity and other characteristics when 5% to 6.3% drystarch in water having a pH of 3 is heated at 92° C. to 95° C. A starchthat is substantially completely inhibited will resist swelling. Astarch that is highly inhibited will swell to a limited extent and showa continuing rise in viscosity, but will not attain a peak viscosity. Astarch that is moderately inhibited will exhibit a lower peak viscosityand a lower percentage breakdown in viscosity compared to the samestarch that is not inhibited. A starch that is lightly inhibited willshow a slight increase in peak viscosity, and a lower percentagebreakdown in viscosity compared to control (uninhibited) starch.

All starches (including starchy flours) are suitable for use in thepresent invention. The starches can be derived from any native source. A“native” starch or flour is one as it is found in nature in unmodifiedform. Typical sources for the starches are cereals, tubers, roots,legumes and fruits. The native source can be corn, pea, potato, sweetpotato, banana, barley, wheat, rice, sago, amaranth, tapioca, sorghum,waxy maize, waxy pea, waxy wheat, waxy tapioca, waxy rice, waxy barley,waxy potato, waxy sorghum, starches having an amylose content of 40% orgreater and the like. In one embodiment, corn starch (in particular,waxy corn starch) is used. Mixtures of different starches may beutilized. The starch may be subjected to one or more purification and/ormodification treatments prior to being heated with the alcoholic mediumand treatment agent. For example, the starch may be treated to reducethe amount of lipid and/or protein present in the starch. The starch maycontain some amount of moisture, e.g., up to about 15% by weight water.

The alcoholic medium generally comprises at least one alcohol,particularly a C1-C4 monoalcohol such as methanol, ethanol, n-propanol,isopropanol, n-butanol, t-butyl alcohol and the like. One or more othersubstances may also be present in the alcoholic medium, such as anon-alcoholic organic solvent (particularly those that are miscible withthe alcohol) and/or water. However, in one embodiment of the inventionthe alcoholic medium does not contain any solvent other than alcoholand, optionally, water. Aqueous alcohols, for example, may be used toadvantage in the process of the invention. The alcoholic medium maycomprise, for instance, 30% to 100% by weight alcohol (e.g., ethanol)and from 0% to 70% by weight water. In one embodiment, the alcoholicmedium contains from 80% to 96% by weight alcohol (e.g., ethanol) andfrom 4% to 20% by weight water, the total amount of alcohol and waterequalling 100%. In another embodiment, the alcoholic medium contains 90%to 100% by weight alcohol (e.g., ethanol) and from 0% to 10% by weightwater, the total amount of alcohol and water equalling 100%. In otherembodiments, not more than 10% or not more than 15% by weight water ispresent in the alcoholic medium. The quantity of alcoholic mediumrelative to starch is not considered to be critical, but typically forthe sake of convenience and ease of processing sufficient alcoholicmedium is present to provide a stirrable and/or pumpable slurry. Forexample, the weight ratio of starch:alcoholic medium may be from about1:2 to about 1:6.

In one aspect of the invention, at least some amount of treatment agent(base and/or salt) is present when the non-pregelatinized granularstarch is heated in the alcoholic medium. However, an advantage of thisembodiment of the present invention is that large amounts of treatmentagent (relative to starch) need not be used in order to achieveeffective inhibition of the starch, in contrast to previously knownstarch modification processes. This simplifies the subsequent processingof the inhibited starch and lowers potential production costs.

Typically, at least 0.5% by weight of treatment agent (based on the dryweight of starch used) is employed, although in other embodiments of theinvention at least 1%, at least 2%, at least 3%, at least 4% or at least5% by weight of treatment agent is present. For economic reasons,generally no more than 10% or 15% by weight of treatment agent ispresent.

Typically, the mixture of starch, alcoholic medium and treatment agentis in the form of a slurry. In certain embodiments of the invention, itmay be desirable to adjust the pH of the slurry to a particular value.It can be difficult to measure the pH of such a slurry due to thepresence of the alcohol. In an embodiment where it is desired to makethe slurry basic by adding a base, a suitable amount of base can bedetermined as if the slurry is a slurry of starch in de-ionized wateralone and then scaled up to the actual amount while keeping the sameratio of base and starch.

The slurry may, for example, be neutral (pH 6 to 8) or basic (pH greaterthan 8). In one embodiment, the pH of the slurry is at least 6. Inanother embodiment, the pH of the slurry is at least 7. The slurry pH inanother embodiment is not more than 12. In other embodiments, the pH ofthe slurry is 6-10, 7.5-10.5 or 8-10. In still other embodiments, the pHof the slurry is 5-8 or 6-7.

The alcohol-treatment agent treatment of the starch may be effected byfirst placing the starch in the alcoholic medium and then addingtreatment agent (e.g., base and/or salt). Alternatively, the treatmentagent may be first combined with the alcoholic medium and then contactedwith the starch. The treatment agent may be formed in situ, such as byseparately adding a base and an acid which react to form the salt whichfunctions as the treatment agent.

Suitable bases for use in the process of the invention include, but arenot limited to, alkali metal and alkaline earth metal hydroxides such aspotassium hydroxide, calcium hydroxide and sodium hydroxide, alkalimetal and alkaline earth metal carbonates such as sodium carbonate,potassium carbonate, sodium bicarbonate, and calcium carbonate, alkalimetal and ammonium salts of phosphorus-containing acids such astetrasodium pyrophosphate, ammonium orthophosphate, disodiumorthophosphate, and trisodium phosphate, and any other bases approvedfor use under the applicable regulatory laws. Strong bases as well asweak bases may be utilized.

Suitable salts for use in the process of the invention includewater-soluble substances which ionize in aqueous solution to provide asubstantially neutral solution (i.e., a solution having a pH of from 6to 8). Alkali metal-containing salts are particularly useful in thepresent invention, as are salts of organic carboxylic acids. In oneembodiment of the invention, the treatment agent includes a salt (inparticular, a sodium or potassium salt) of a polycarboxylic acid such ascitric acid or the like. Other suitable carboxylic acid salts include,but are not limited to, salts of acetic acid, adipic acid, itaconicacid, malonic acid, lactic acid, tartaric acid, oxalic acid, fumaricacid, aconitic acid, succinic acid, oxalosuccinic acid, glutaric acid,ketoglutaric acid, malic acid, fatty acids and combinations thereof.Sodium citrates (monosodium citrate, disodium citrate, trisodium citrateand combinations thereof) are utilized in one aspect of the presentinvention. Other illustrative examples of suitable carboxylic acid saltsinclude, but are not limited to, potassium citrates, calcium citrates,sodium malate, sodium fumarate, sodium oxalate and the like andcombinations thereof. In one embodiment of the invention, one or moresalts capable of functioning as buffering agents are employed.

Mixtures of different treatment agents may be used in the presentinvention. For example, the starch may be heated in the alcoholic mediumin the presence of both at least one base and at least one salt.

The starch, alcoholic medium and treatment agent are heated for a timeand at a temperature effective to inhibit the starch to the desiredextent. Generally speaking, temperatures in excess of room temperature(i.e., 35° C. or greater) will be necessary. At the same time, extremelyhigh temperatures should be avoided. The heating temperature can be, forexample, 35° C. to 200° C. Typically, temperatures of from 100° C. to190° C., 120° C. to 180° C., or from 130° C. to 160° C., or from 140° C.to 150° C. will be sufficient. The heating time generally is at least 5minutes but no more than 20 hours and typically 40 minutes to 2 hours.In general, a desired level of starch inhibition may be achieved morerapidly if the heating temperature is increased.

The specific conditions of time of treatment, temperature of treatment,and proportions of the components of the mixture of starch, alcoholicmedium and treatment agent are generally selected such that the starchis not gelatinized to a significant extent. That is, the starch remainsnon-pregelatinized. Thus, in various embodiments of the invention, notmore than 30% or not more than 20% or not more than 10% of the starchgranules lose birefringence as a resulting of such processing.

When the temperature selected for the heating step exceeds the boilingpoint of one or more components of the alcoholic medium, it will beadvantageous to carry out the heating step in a vessel or otherapparatus capable of being pressurized. The treatment may be conductedwithin a confined zone in order to maintain the alcoholic medium in aliquid state. Additional positive pressure could be employed, but isgenerally not necessary. The starch may be slurried in the alcoholicmedium together with the treatment agent under conditions of elevatedtemperature and pressure and treated for a time sufficient to change thestarch's viscosity characteristics. Such treatment may be conducted in astirred tank reactor on a batch basis or in a tubular reactor on acontinuous basis, although other suitable processing techniques will beapparent to those skilled in the art. In another embodiment, the starchmay be in the form of a bed within a tubular reactor and a mixture ofthe alcoholic medium and treatment agent passed through such bed(optionally, on a continuous basis), with the bed being maintained atthe desired temperature to effect inhibition of the starch.

In embodiments of the invention wherein a base has been utilized as atreatment agent, the mixture of starch, alcoholic medium and base may becombined with one or more acids, once the heating step is completed, forthe purpose of neutralizing the base. Suitable acids for use in suchneutralization step include, but are not limited to,phosphorus-containing acids such as phosphoric acid, carboxylic acidssuch as acetic acid, adipic acid, itaconic acid, malonic acid, lacticacid, tartaric acid, oxalic acid, fumaric acid, aconitic acid, succinicacid, oxalosuccinic acid, glutaric acid, ketoglutaric acid, malic acid,fatty acids and combinations thereof, as well as other types of acidssuch as uric acid. If the inhibited starch is intended for use as a foodingredient, the acid generally should be selected to be one that ispermitted for such use under applicable regulations. Typically,sufficient acid is added to lower the pH of the mixture to about neutralto slightly acidic, e.g., a pH of from about 5 to about 7 or from about6 to about 6.5.

The neutralization with acid may be carried out at any suitabletemperature. In one embodiment, the slurry of starch, base and alcoholicmedium is cooled from the heating temperature used to approximately roomtemperature (e.g., about 15° C. to about 30° C.) prior to being combinedwith the acid to be used for neutralization. The neutralized mixture maythereafter be further processed as described below to separate theinhibited starch from the alcoholic medium. In another embodiment of theinvention, however, neutralization of the base is followed by furtherheating of the starch slurry. Such further heating has been found to becapable of modifying the rheological properties of the inhibited starchobtained, as compared to the viscosity characteristics of an analogouslyprepared starch that has not been subjected to heating afterneutralization of the base.

Generally speaking, such further heating step is advantageously carriedout at temperatures in excess of room temperature (i.e., 35° C. orgreater). At the same time, extremely high temperatures should beavoided. The heating temperature can be, for example, 35° C. to 200° C.Typically, temperatures of from 100° C. to 190° C., 120° C. to 180° C.,or from 130° C. to 160° C., or from 140° C. to 150° C. will besufficient. The heating time generally is at least 5 minutes but no morethan 20 hours and typically 40 minutes to 2 hours.

In embodiments of the invention wherein a salt (such as a sodium salt ofcitric acid) has been employed as the treatment agent, it may beadvantageous to cool the starch/treatment agent/alcoholic medium mixturefairly rapidly to approximately room temperature after heating of themixture has been carried out for the desired period of time. It has beendiscovered that under at least some conditions that such rapid coolingmay provide a more highly inhibited starch as compared to a starchobtained by slower cooling of the starch/treatment agent/alcoholicmedium mixture following the heat treatment step.

The mixture of starch and alcoholic medium may be processed so as toseparate the starch from the alcoholic medium. Conventional methods forrecovering particulate solids from liquids such as filtration,decantation, sedimentation or centrifugation may be adapted for suchpurpose. The separated starch may optionally be washed with additionalalcoholic medium and/or alcohol and/or water to remove any undesiredsoluble impurities. In one embodiment, neutralization of residual baseis accomplished by washing the recovered starch with an acidified liquidmedium. Drying of the separated starch will provide an inhibitednon-pregelatinized granular starch in accordance with the invention. Forexample, drying may be performed at a moderately elevated temperature(e.g., 30° C. to 60° C.) in a suitable apparatus such as an oven or afluidized bed reactor or drier or mixer. Vacuum and/or a gas purge(e.g., a nitrogen sweep) may be applied to facilitate removal ofvolatile substances (e.g., water, alcohol) from the starch. Theresulting dried inhibited non-pregelatinized granular starch may becrushed, ground, milled, screened, sieved or subjected to any other suchtechnique to attain a particular desired particle size. In oneembodiment, the inhibited starch is in the form of a free-flowing,granular material.

In one embodiment of the invention, however, the starch is subjected toa desolventization step at a significantly higher temperature (e.g.,greater than 80° C. or greater than 100° C. or greater than 120° C.).Excessively high temperatures should be avoided, however, sincedegradation or discoloration of the starch may result. Such a step notonly reduces the amount of residual solvent (alcohol) in the product butalso provides the additional unexpected benefit of enhancing the degreeof inhibition exhibited by the starch. Desolventization temperaturescan, for example, be about 100° C. to about 200° C. Typical temperaturesare 120° C. to 180° C. or 150° C. to 170° C. The desolventization may becarried out in the presence or in the absence of steam. Steam treatmenthas been found to be advantageous in that it helps to minimize theextent of starch discoloration which may otherwise occur at such anelevated temperature. In one embodiment of the invention, steam ispassed through a bed or cake of the inhibited starch. The starchdesolventization methods of U.S. Pat. No. 3,578,498, incorporated hereinby reference in its entirety for all purposes, may be adapted for use inthe present invention. Following steam treatment, the inhibited starchmay be dried to reduce the residual moisture content (e.g., by heatingin an oven at a temperature of from about 30° C. to about 70° C. or in afluidized bed reactor).

In one embodiment, the treated starch, which has been recovered from thealcoholic medium, is first brought to a total volatiles content of notmore than about 35% by weight or not more than about 15% by weight. Thiscan be accomplished, for example, by first air or oven drying therecovered starch at moderate temperature (e.g., 20° C. to 70° C.) to thedesired initial volatiles content. Live steam is then passed through thedried starch, the system being maintained at a temperature above thecondensation point of the steam. A fluid bed apparatus may be used toperform such a steam desolventization step.

In general, it will be desirable to carry out desolventization underconditions effective to result in a residual alcohol content in theinhibited starch of less than 1 weight % or less than 0.5 weight % orless than 0.1 weight %.

Following desolventization, the inhibited starch may be washed withwater and then re-dried to further improve color and/or flavor and/orreduce the moisture content.

The resultant starches are functionally similar to chemicallycrosslinked starches in that they may have a non-cohesive, smoothtexture when cooked out (e.g., to maximize their functionality orperformance in a selected application) or gelatinized (e.g., the starchno longer exhibits birefringence or Maltese crosses when illuminatedusing polarized light), and/or excellent tolerance to processingvariables such as heat, shear and extremes of pH, particularly for asignificant time under such conditions. Also, the viscosity on cookinginitializes (starts to build) at a later or substantially the same timeas the same starch which has not been inhibited in accordance with thepresent invention. Such inhibited starches may also provide a desirablesmooth texture to the processed food product and maintain their capacityfor thickening throughout processing operations. In addition, theinhibited starch will have less viscosity breakdown than the same starchwhich has not been treated using the process of the present invention.

The inhibited non-pregelatinized granular starches obtained by practiceof this invention may be blended with other unmodified or modifiedstarches or with other food ingredients before use in a food product.The inhibited starches may be used in place of the chemically modifiedor crosslinked starches presently used in foods, yet maintain a cleanlabel (non-modified label).

Food products wherein the inhibited starches are useful includethermally-processed foods, acid foods, dry mixes, refrigerated foods,frozen foods, extruded foods, oven-prepared foods, stove top-cookedfoods, microwaveable foods, full-fat or fat-reduced foods, and foodshaving a low water activity. Food products wherein the inhibitedstarches are particularly useful are foods requiring a thermalprocessing step such as pasteurization, retorting, or ultra hightemperature (UHT) processing. The inhibited starches are particularlyuseful in food applications where stability is required through allprocessing temperatures including cooling, freezing and heating.

The inhibited starches are also useful in food products where anon-chemically crosslinked starch thickener, viscosifier, gelling agent,or extender is required or desirable. Based on processed foodformulations, the practitioner may readily select the amount and type ofinhibited non-pregelatinized starch required to provide the necessarythickness and gelling viscosity in the finished food product, as well asthe desired texture. Typically, the starch is used in an amount of0.1-35%, e.g., 2-6%, by weight, of the food product.

Among the food products which may be improved by the use of theinhibited non-pregelatinized granular starches are high acid foods (pH<3.7) such as fruit-based pie fillings, baby foods, and the like; acidfoods (pH 3.7-4.5) such as tomato-based products; low acid foods(pH >4.5) such as gravies, sauces, and soups; stove top-cooked foodssuch as sauces, gravies, and puddings; instant foods such as puddings;pourable and spoonable salad dressings; refrigerated foods such as dairyor imitation dairy products (e.g., yogurt, sour cream, and cheese);frozen foods such as frozen desserts and dinners; microwaveable foodssuch as frozen dinners; liquid products such as diet products andhospital foods; dry mixes for preparing baked goods, gravies, sauces,puddings, baby foods, hot cereals, and the like; and dry mixes forpredusting foods prior to batter cooking and frying. The inhibitedstarches are also useful in preparing food ingredients such asencapsulated flavors and clouds.

Inhibited starches prepared in accordance with the present invention mayalso be used in various non-food end use applications where chemicallymodified (crosslinked) inhibited starches have conventionally beenutilized, such as cosmetic and personal care products, paper, packaging,pharmaceutical formulations, adhesives, and the like.

EXAMPLES Starch Treatment Method A

In this example, starch is first heated in an alcoholic medium in thepresence of base (sodium carbonate), followed by neutralization at alower temperature. After separating the bulk of the alcohol from theinhibited starch, the inhibited starch is subjected todrying/desolventization.

Summary of Treatment Procedure:

-   -   1. Weigh out 3A ethanol (94% by weight) 1177 g.    -   2. Add 308 g waxy starch (89% dry starch or d.s.) to ethanol        while stirring.    -   3. Add sodium carbonate (either 0.7%, 1.4%, 2.8% or 5.53% by        weight, based on dry starch).    -   4. Transfer the mixture of starch, alcohol and sodium carbonate        into a 2-liter high pressure stainless steel reactor equipped        with agitation and controlled steam heating through its jacket.    -   5. Heat the slurry in the reactor to a designated temperature        (143° C.) and hold at that temperature for 60 min.    -   6. Cool the reactor to 35° C.    -   7. Open vent to equalize pressure.    -   8. Neutralize the slurry to about pH 6 using 50% citric acid        solution (either 0.843%, 1.685%, 3.37% or 6.75% by weight citric        acid based on dry starch) using a syringe through a vent.    -   9. Stir for 30 min.    -   10. Open the lid.    -   11. Remove slurry from the reactor.    -   12. Filter the slurry using a filter paper on a Buchner funnel.    -   13. Take out and crumble wet cake onto tray in hood and leave        for several hours/or overnight before putting in oven. This        allows much of the 3A alcohol to evaporate.    -   14. Dry starch at 50° C. in convection oven overnight.    -   15. Grind and pass starch through 100 mesh sieve and label.    -   16. Dry starch at 125 or 160° C. in convection oven for 4 hours        for desolventization.        Desolventization with Steam:    -   1. Weigh out 3.5 kg DI water in a steel container (7.2″        diameter, 8.5″ tall).    -   2. Put the steel container with water in an oven (Yamato DKN 600        mechanical convection oven, Fisher Scientific Inc.) at 160° C.        for 1 hour.    -   3. Weigh and spread 50 g of alcohol-base treated starch        (alcohol-base treated starch from procedure step 15 above) on a        500 mesh sieve and place it on a shelf directly on top of the        water container.    -   4. Desolventize the starch at 160° C. for 4 hours.    -   5. Dry starch at 50° C. overnight in an oven.

Rapid Visco-Analyser Measurement of Starch:

A rapid visco-analyser (RVA) (Newport Scientific Pty. Ltd., Warriewood,Australia) was used to analyze starch pasting profiles. Starchconcentrations were varied to give a peak paste viscosity of about 1000centipoise (cP). In this study, starch concentrations of 5% and 6.65%were used. Heating profiles and RPM are indicated in each graph. RVA pH6.5 solution (Cat. No. 6654-5, RICCA Chemical Company, Arlington, Tex.,USA) and the certified buffer pH 3.5 solution (Key Laboratory Services,2363 Federal Drive, Decatur, Ill.) were used. The Cookup RVA profile isintended to measure the RVA viscosity of cook-up waxy starch. Starch wasweighed into an RVA cup and RVA pH 6.5 or pH 3.5 solutions were added toa total weight of 28 g. The Instant RVA profile was intended to analyzeinstant starches. Starch was weighed into the RVA cup and 4.5 gpropylene glycol was added for dispersion of the starch. The mixture wasstirred with a spatula to make sure complete dispersion was achieved.RVA pH 6.5 solution was added to a total weight of 32 g. The starchslurry was mixed at 35° C. for 20 min at the initial stage to developpaste viscosity of instant starches.

Microscopy of Starch Paste:

Starch paste was diluted with distilled water to about 1% starch. Onedrop of starch solution was added to a microscope slide and dyed withiodine tincture (2% O.S.P.) or solution containing 0.2% I₂ and 2% KI. Acover slip was added on top of each sample. The slide with dyed starchsample was observed using a Leica Microscope DM4000 M (Buffalo Grove,Ill. 60089 United States). A 20× objective lens and 10× binoculars undertransmitted light were used. Starch granules stained with solutioncontaining 0.2% I2 and 2% KI and illuminated with polarized light werealso observed using this microscope.

Specific Sedimentation Volume of Starch After RVA Cooking:

Specific sedimentation volume (SSV) is defined as the bulk volumeoccupied by swollen starch granules per mass unit of dry starch (mL/g).Each starch was cooked using a Rapid-Visco analyzer (RVA) under thefollowing conditions: dry solids percent (DS%)=2.5% dry starch in theslurry; 38 g total slurry; Cookup RVA profile (160 rpm, 20 min at 95°C., cool down to 50° C., total run 35 min); pH 6.5 phosphate buffer. Thewater loss during the RVA was accounted for by weighing before and aftercooking. The paste was then transferred into a tared 30-mL centrifugetube without dilution, weighed, and centrifuged at 4000 rpm for 15minutes in a bench-top Sorvall Legend T+ centrifuge. The sediment volumewas read after the supernatant had been decanted. SSV (mL/g)=(mLsediment after 15 min at 4000 rpm)/(g paste in 30 mL*dry starch content% in the paste). Starch with SSV between 20 mL/g to 40 mL/g isconsidered having low shear stability or low cross-linked in chemicallycross-linked starch. Starch with SSV between 16 mL/g to 20 mL/g hasmedium shear stability and starch with SSV<16 mL/g has high shearstability.

Starch Color Measurement:

Color was measured using a Hunter Colorflex reflective spectrophotometer(Hunterlabs, Reston, Va.).

Retort Simulation Using Physica MCR 301 Rheometer with Pressure Cell:

A Physica MCR 301 Rheometer (Anton Paar Germany GmbH, Ostfildern,Germany) was used to simulate retort processing. Starch was weighed intoa cup and RVA pH 6.5 solution (Cat. No. 6654-5, RICCA Chemical Company,Arlington, Tex., USA) was added to a total weight of 25 g of slurry. Thepercentage of starch should be high enough to give a viscosity of aboveabout 1000 mPa·s at 120° C. A higher concentration of starch is requiredfor a more highly inhibited starch. 20 g slurry was loaded to thepressure cell using a syringe. A two wing stirrer (ST24/PR-2W-A1) wasused. There is an initial heating to 60° C., then the sample is held at60° C. to record the viscosity, followed by slow heating to 120° C.(typical retort temperature) with a 5 minute hold. The starch slurry isthen cooled in 2 stages for double record of viscosity stability atmedium hot (70° C.) and cold (25° C.) temperatures. The system is undera “high” shear at a shear rate of 177 min⁻¹ during the heating andcooling phases in order to ensure product homogeneity and a “low” shearat a shear rate of 29.3 min⁻¹ during the high temperature (120° C.) holdstep to maximize viscosity reading and enhance differences betweenbatches. The viscosity curve during 5 min holding time at 120° C. isimportant for retort stability. An upward curve or line at 120° C.holding time indicates swelling of starch granules and highly inhibitedstarch. A downward curve or line indicates breakdown of pastes. Thepastes after measurements were examined under a microscope.

Results and Discussion (Starch Treatment Method A)

As previously described, waxy starch was treated in alcohol with sodiumcarbonate (1.4% based on dry starch) at 143° C. for 1 hour and thenneutralized with citric acid. The treated waxy starch was collected byfiltration. Additional alcohol was removed by evaporation in the hoodovernight, drying in a forced air oven at 50° C. and then at 160° C.with or without steam (desolventization) for 4 hours.

FIG. 1 shows the RVA profiles (Cookup) (5% and pH 6.5) of waxy starch(Sample 1-D), waxy starch after alcohol-base treatment at 143° C. for 1hr (Sample 1-A), and waxy starch after alcohol-base treatment at 143° C.for 1 hr and desolventization at 160° C. with (Sample 1-C) or without(Sample 1-B) steam for 4 hours. Alcohol-base treatment alone reduced theRVA breakdown (the peak or maximum viscosity minus the trough or minimumviscosity after the peak) by about 50% and increased the final viscosityby about 43%. The micrographs of the pastes after RVA analyses showedthat the waxy starch paste was dispersed while the starch paste of waxystarch after alcohol-alkaline treatment contained swollen granuleremnants (broken swollen granules) (FIG. 2), which indicated thatalcohol-base treatment helped to maintain swollen granule remnants butwas not enough to hold the swollen granule structure. Desolventizationwith or without steam after alcohol-base treatment eliminated the RVAbreakdowns (FIG. 1). Alcohol-base treated waxy starch desolventizedwithout steam has a lower RVA final viscosity than that desolventizedwith steam. The micrographs of pastes after RVA analyses showed thatstarch pastes of alcohol-alkaline treated waxy starch desolventized withor without steam both maintained the starch granule structure. Specificsedimentation volume (SSV) measurements indicated higher inhibition ofalcohol-alkaline treated waxy starch desolventized without steamcompared to that with steam (Table 1), probably caused by the lessswelling of starch granules of the former during RVA. However, drystarch (less than 1% moisture) at a high temperature is an explosionhazard; therefore desolventization with steam is considered a saferprocess in an industrial scale. In addition, desolventization at 160° C.with steam produced less color in the product than that desolventizedwithout steam (Table 2).

TABLE 1 Alcohol-Base SSV, Sample Treatment Desolventization mL/g 1-DNone None 39 1-A 1.4% Na₂CO₃, None 39 143° C., 1 hr 1-B 1.4% Na₂CO₃,160° C., 4 hrs 13 143° C., 1 hr 1-C 1.4% Na₂CO₃, Steam, 160° C., 18 143°C., 1 hr 4 hrs

TABLE 2 Alcohol-Base Whiteness Yellowness Sample TreatmentDesolventization Index Index 1-B 1.4% Na₂CO₃, 160° C., 4 hrs 41.5 17.8143° C., 1 hr 1-C 1.4% Na₂CO₃, Steam, 160° C., 50.9 14.8 143° C., 1 hr 4hrs

Positive slopes were maintained (no breakdown in viscosity of thepastes) in alcohol-base treated waxy starches after desolventizationwith and without steam during RVA analyses using 5% sample concentrationin pH 3.5 buffer (FIG. 3), indicating that the pastes were stable inacidic conditions. Micrographs of the pastes after RVA using pH 3.5buffer showed granular structure in the desolventized samples (FIG. 4).

Retort simulation using a rheometer was employed to simulate retortprocessing at 120° C. in soup production to test the stability of starchpastes under high temperature conditions. In this test, starches withslightly negative, zero or positive slopes at 120° C. holding time arepotentially acceptable for soup and other high temperature applications.Native waxy starch is not suitable for soup and foods requiring hightemperature processing by this criterion. Alcohol-base treated waxystarch without desolventization is not an ideal candidate. Alcohol-basetreated waxy starches desolventized with and without steam at 160° C.are potentially suitable for soup and foods requiring high temperatureprocessing. Micrographs of the pastes after retort simulation are shownin FIG. 5. Starch pastes of alcohol-base treated waxy starchdesolventized with and without steam both maintained the starch granulestructure, which provided structural evidence that they were retortstable.

Samples of non-pregelatinized granular starches after alcohol-basetreatment followed by desolventization which were illuminated withpolarized light exhibited the microscopic images shown in FIG. 6; theirRVA profiles are shown in FIG. 7. Native starch granules showbirefringence or a typical Maltese cross when viewed in polarized light.This property (exhibition of a Maltese cross) is brought about becausethe starch molecules are radially oriented within the granule. Whenstarch is heated in water, birefringence (Maltese cross pattern) inpolarized light is lost by the end of starch gelatinization. FIG. 6shows that the Maltese cross patterns of starch granules are virtuallyunchanged when waxy starch is processed with alcohol-base treatmentfollowed by desolventization with or without steam, which indicates thatthe starches are non-pregelatinized. Pregelatinized starch developsviscosity in RVA using the Instant profile in the initial 20 minutes at35° C. before further heating up. Pregelatinized instant waxy starch(XPAND'R SC, a Tate & Lyle commercial product) developed viscosityimmediately at 35° C. while native waxy starch and waxy starches afteralcohol-alkaline treatment followed by desolventization did not developdiscernible viscosity until they were heated to a higher temperature,which suggested they are non-pregelatinized starches.

Waxy starch was treated in alcohol with various amounts of sodiumcarbonate (0.7%, 1.4%, 2.8% and 5.53% based on dry starch) at 143° C.for 1 hour and then neutralized with citric acid. Desolventization wasconducted at 125 or 160° C. for 4 hours. Table 3 shows that increasingamounts of sodium carbonate and citric acid for neutralization tend toresult in decreasing SSV values (higher inhibition) of the products. Thesame alcohol-base treated starch desolventized at a high temperature(160° C.) gave more inhibited products (lower SSV values) than whendesolventized at a lower temperature (125° C.). The product treatedusing 5.53% sodium carbonate and desolventization at 160° C. wasinhibited more than Starches A-C, which were commercially availableinhibited or modified starches.

TABLE 3 Alcohol-Base SSV, Sample Treatment Desolventization mL/g 2-A5.53% Na₂CO₃, 125° C., 4 hrs 24 143° C., 1 hr 2-B 5.53% Na₂CO₃, 160° C.,4 hrs  9 143° C., 1 hr 2-C  2.8% Na₂CO₃, 125° C., 4 hrs 27 143° C., 1 hr2-D  2.8% Na₂CO₃, 160° C., 4 hrs 11 143° C., 1 hr 2-E  1.4% Na₂CO₃, 125°C., 4 hrs 30 143° C., 1 hr 2-F  1.4% Na₂CO₃, 160° C., 4 hrs 13 143° C.,1 hr 2-G  0.7% Na₂CO₃, 125° C., 4 hrs 33 143° C., 1 hr 2-H  0.7% Na₂CO₃,160° C., 4 hrs 16 143° C., 1 hr Starch A N/A N/A 24 Starch B N/A N/A 18Starch C N/A N/A 13

FIG. 8 shows the RVA profiles of waxy starch after being treated inalcohol with various amounts of sodium carbonate and desolventized at160° C. for 4 hours and a Tate & Lyle commercial chemically modifiedwaxy starch with high cross-linking. All the samples showed no RVAbreakdown after alcohol-base treatment. The viscosities of treated waxystarches decreased with increasing amounts of sodium carbonate in thealcohol-base treatment and citric acid in the neutralization thereafter.The alcohol-base treated samples behaved like chemically cross-linkedstarches in the RVA analysis.

These same alcohol-base treated samples were desolventized at a lowtemperature (125° C.) and their RVA profiles are shown in FIG. 9.Significantly less inhibition was exhibited by the samples desolventizedat a low temperature (FIG. 9). The RVA breakdown increased withdecreasing amounts of sodium carbonate (from 5.53% to 0.7%).

The acid stabilities of alcohol-base treated samples which weredesolventized at 160° C. were tested using RVA in a pH 3.5 buffer (FIG.10). No RVA breakdown was observed in the RVA profiles, indicated thatthese treated starches were acid stable. Significant RVA breakdowns wereexhibited by the samples desolventized at 125° C. with breakdownincreasing with decreasing amounts of sodium carbonate (from 5.53% to0.7%) (FIG. 11).

The high temperature stabilities of starches were tested using a PhysicaMCR 301 Rheometer. The viscosities of alcohol-base treated samplesprepared using 2.8%, 1.4% and 0.7% sodium carbonate in alcohol treatmentfollowed by desolventization at 160° C. showed increases in 5 minuteholding time at 120° C., which indicated no breakdown of paste and pastestability at a high temperature.

FIGS. 12, 13, 14 and 15 show micrographs of starch granules in thepastes after RVA and retort simulation using a Physica MCR 301Rheometer. When alcohol-base treated starches were desolventized at 160°C., intact swollen starch granules were clearly visible. The intactswollen starch granules after RVA and retort simulation clearlydemonstrated the inhibition of starch granules after treatment inaccordance with the invention. When alcohol-base treated samples weredesolventized at 125° C., the starch granules swelled more than starchesdesolventized at 160° C. and some swollen starches were broken down. Theextent of starch granule breakdown was inversely related to the amountsof sodium carbonate and the amounts of citric acid used during theneutralization thereafter.

Starch Treatment Method B

In this example, starch is treated using a procedure involving two heatcycles wherein the starch was first heated with base in an alcoholicmedium and then further heated following addition of citric acid toneutralize the base (providing a pH of about 6).

Waxy starch (308 g, 11% moisture) was added to 3A ethanol (1177 g; 7.18%water) while stirring. Anhydrous sodium carbonate (7.585 g; 2.77% byweight based on dry starch) was then added. The resulting slurry wastransferred into a two liter high pressure stainless steel reactorequipped with agitation and controlled steam heating through its jacket.The slurry was heated in the reactor with agitation to 143° C. and heldat that temperature for 60 minutes. After cooling the reactor contentsto 25° C., the slurry was neutralized using 18.5 g of a 50% citric acidsolution (3.37% by weight based on dry starch). The reactor contentswere again heated to 143° C. with agitation and kept at that temperaturefor 60 minutes. After cooling to 25° C., the slurry was filtered throughfilter paper in a Buechner funnel to provide a wet cake of starch. Thewet cake was crumbled onto a tray and left for several hours in a hoodfor several hours before being put into an oven, to allow much of the 3Aalcohol to evaporate. The starch (identified hereafter as “7629-68”) wasthereafter dried at 50° C. in a convection oven overnight and thenground and passed through a 100 mesh sieve.

Desolventization of the starch with steam was carried out by placing 3.5kg deionized water in a steel container (7.2″ diameter, 8.5″ tall),heating the steel container in an oven at 125° C. for 1 hour, spreading50 g of the treated starch on a 500 mesh sieve and placing it on a shelfdirectly on top of the steel container, and desolventizing the starch at125° C. for 4 hours. The starch was then dried overnight in a 50° C.oven.

Rapid Visco-Analyser Measurement of Starch

A Rapid Visco-Analyser (RVA) (Newport Scientific Pty. Ltd., Warriewood,Australia) was used to analyze starch pasting profiles. A starchconcentration of 5% was used in the RVA slurry. Heating profiles and RPMare indicated in each graph. A RVA pH 6.5 buffer solution (Cat. No.6654-5, RICCA Chemical Company, Arlington, Tex., USA) and a certifiedbuffer pH 3.5 solution (Key Laboratory Services, 2363 Federal Drive,Decatur, Ill.) were used. The Viswaxy RVA profile with a 20-minute holdat 95° C. is intended to measure the RVA viscosity of cook-up waxystarches. Starch was weighed into a RVA cup and RVA pH 6.5 or pH 3.5solutions were added to a total weight of 28 g.

Method for Measuring Sedimentation Volumes With and Without Shearing

-   -   1. Measure moisture of the starch.    -   2. Weigh 5% ds starch in a 250 mL wide-mouthed sample glass jar        and add DI water or 1% NaCl solution to 100 g.    -   3. Record the weight of the jar (optional).    -   4. Place the jar in a water bath at 95° C. and stir the contents        using a glass rod for 3 min while heating.    -   5. Remove the glass jar and secure it with a cap.    -   6. Place the jar into another water bath shaker at 95° C.        (Boekel Shaker hot tub).    -   7. Cook the sample at 95° C. for 20 min with orbital shaking at        120 rpm.    -   8. After 20 min, take the sample from the shaker and place it        another water bath at room temp and cool the starch paste.    -   9. Record the weight of the jar (optional).    -   10. Add ˜40-50 mL of DI water or 1% NaCl solution to a 100 mL        graduated cylinder and add 20.0 g of the cooked starch paste.        Fill the rest of the volume (100 mL mark) with DI water or 1%        NaCl solution.    -   11. Seal the graduated cylinder with paraffin and shake the        contents to form a uniformly distributed starch suspension (1%        ds).    -   12. Set aside the graduated cylinder without any disturbance.    -   13. Record the sediment volume after 24 h.    -   14. For measurement of sedimentation volume after shearing, add        50 g of the starch paste in water or 1% NaCl solution into the        blender. Shear at 35 V setting for starch in water and 25 V        setting for starch in 1% NaCl solution for 20 sec. Follow the        usual sedimentation procedure of the sheared starch paste.

Microscopy of Starch Paste:

-   -   1. Put 20 μL of as-is starch paste (5%) onto a microscopy glass        slide.    -   2. Apply 20 μL of 0.02 N iodine stock solution onto the paste.    -   3. Use a tooth pick to blend the paste and the iodine evenly on        the glass slide.    -   4. Apply a piece of cover glass onto the blend and examine the        sample using a 5× objective lens and 10× binoculars under        transmitted light on the Leica DM4000 optical microscope.    -   5. Go through the whole area of sample under the cover glass and        take images with granule concentration that is representative of        the entire sample.    -   6. For un-sheared starch paste sample, number of intact granules        is counted as the total number of intact waxy granules in the        50× magnification image.    -   7. For sheared starch paste sample, number of intact granules is        counted manually since the microscopy image has to be magnified        to tell intact waxy granules apart from fragments.    -   8. Percentage of fragmentation=(number of intact waxy granules        in un-sheared sample—number of intact waxy granules in sheared        sample)/number of intact waxy granules in un-sheared sample.

Microscopy of Starch Under Polarized Light:

Starch (10 mg) was placed on a microscope slide. A drop of distilledwater was added and mixed with starch. A cover slip was added on top ofa sample. The slide with starch sample was observed using the LeicaMicroscope DM4000 M (Buffalo Grove, Ill. 60089 United States)illuminated with polarized light using a 20× objective lens and 10×binoculars.

Results and Discussion (Starch Treatment Method B)

Table 4 shows the sedimentation volumes in 1% NaCl of thealcohol-alkaline treated starch before and after desolventization at125° C. and 160° C.

TABLE 4 Sedimentation Volumes (mL) and Fragmented Cooked Starch Granulesafter Shear in 1% NaCl solution Sedimentation Volume (mL) MicroscopySheared 25 % Fragmented Sample Unsheared Volts for 20 sec Granules7629-68, 2.77% Na₂CO₃, 21 20 21% 2HC 7629-68, 2.77% Na₂CO₃, 22 19.5 17%2HC, desol 125° C. 7629-68, 2.77% Na₂CO₃, 17.8 16 14% 2HC, desol 160° C.

Table 5 shows the sedimentation volumes of the alcohol-alkaline treatedsamples of 7629-68 before and after desolventization at 125° C. and 160°C. in water, which exhibited higher sedimentation volumes than thoseobserved in 1% NaCl solution.

TABLE 5 Sedimentation Volumes (mL) and Fragmented Cooked Starch Granulesafter Shear in Purified Water Sedimentation Volume (mL) MicroscopySheared 35 % Fragmented Sample Unsheared Volts for 20 sec Granules7629-68, 2.77% Na₂CO₃, 25 27 13% 2HC 7629-68, 2.77% Na₂CO₃, 26 26 11%2HC, desol 125° C. 7629-68, 2.77% Na₂CO₃, 21 20 14% 2HC, desol 160° C.

The RVA profiles of the alcohol-alkaline treated samples 7629-68 beforeand after desolventization at 125° C. and 160° C. are shown in FIG. 16(RVA pH 6.5) and FIG. 17 (RVA pH 3.5).

FIGS. 18 and 20 are micrographs of starch cooked in 1% NaCl as preparedfor measuring the un-sheared sedimentation volumes. FIGS. 19 and 21 aremicrographs of starch cooked in 1% NaCl and then sheared using a blenderas prepared for measuring the sheared sedimentation volumes. Nosignificant fragmentation of granules was observed.

Native starch granules show birefringence or a typical Maltese crosswhen viewed in polarized light. When starch is heated in water,birefringence or Maltese cross in polarized light is lost by the end ofstarch gelatinization. FIGS. 22 and 23 show that Maltese crosses ofstarch granules are preserved when waxy starch has been processed usingalcohol-alkaline treatment with two heating cycles and desolventized at125° C. and 160° C., which indicates that the starch isnon-pregelatinized.

Sedimentation volumes are used to measure the extent of inhibition ofstarch in the above-described study. A smaller un-sheared sedimentationvolume indicates less swelling of cooked starch granules and a higherinhibition. A smaller change of sheared sedimentation volumes comparedto un-sheared sedimentation volumes indicates a higher shear stability.By these standards, it was shown that the alcohol-alkaline treatedsamples 7629-68 before and after desolventization were very highlyinhibited and shear stable. RVA profiles also showed that samples7629-68 before and after desolventization were highly inhibited.

The micrographs of cooked starch in 1% NaCl before (FIGS. 18 and 20) andafter shearing using a blender (FIGS. 19 and 21) at 25 Volts for 20 secshow no significant fragmentation of gelatinized granules.

Maltese crosses of starch granules are preserved when waxy starch hasbeen processed using alcohol-alkaline treatment with two heating cyclesand desolventization, which indicates that the starch isnon-pregelatinized.

Starch Treatment Method C

In this method, starch is heated in an alcoholic medium in which sodiumcarbonate and citric acid had been introduced, wherein the sodiumcarbonate is essentially neutralized by the citric acid (thus formingsodium salts of citric acid in situ).

Waxy starch (307 g, 10.7% moisture) was added to 3A ethanol (1177 g;7.18% water) while stirring. Anhydrous sodium carbonate (7.585 g; 2.77%by weight based on dry starch) and 18.5 g 50% citric acid solution(3.37% by weight based on dry starch) were then added. The resultingslurry was transferred into a two liter high pressure stainless steelreactor equipped with agitation and controlled steam heating through itsjacket. The slurry was heated in the reactor with agitation to 143° C.and held at that temperature for 60 minutes. After cooling to 25° C.,the slurry was filtered through filter paper in a Buechner funnel toprovide a wet cake of starch. The wet cake was crumbled onto a tray andleft for several hours in a hood for several hours before being put intoan oven, to allow much of the 3A alcohol to evaporate. The starch(identified hereafter as “7629-70”) was thereafter dried at 50° C. in aconvection oven overnight and then ground and passed through a 100 meshsieve.

Desolventization of the starch with steam was carried out by placing 3.5kg deionized water in a steel container (7.2″ diameter, 8.5″ tall),heating the steel container in an oven at 125° C. for 1 hour, spreading50 g of the treated starch on a 500 mesh sieve and placing it on a shelfdirectly on top of the steel container, and desolventizing the starch at125° C. for 4 hours. The starch was then dried overnight in a 50° C.oven.

The starch obtained was characterized using the same proceduresdescribed previously for the starch produced using Starch TreatmentMethod B.

Results and Discussion (Starch Treatment Method C)

Table 6 shows the sedimentation volumes in 1% NaCl of inhibited starchmade using one heating cycle with sodium carbonate and citric acid inalcohol before and after desolventization.

TABLE 6 Sedimentation Volumes (mL) and Fragmented Cooked Starch Granulesafter Shear in 1% NaCl solution Sedimentation Volume (mL) MicroscopySheared at % Fragmented Sample Unsheared 25 Volts Granules 7629-70 23  22.5 21 7629-70 desol 125° C. 22.5 21.5 16

Table 7 shows the sedimentation volumes in purified water of inhibitedstarch made using one heating cycle with sodium carbonate and citricacid in alcohol before and after desolventization. The sedimentationvolumes were higher than those observed in 1% NaCl solution.

TABLE 7 Sedimentation Volumes (mL) and Fragmented Cooked Starch Granulesafter Shear in Purified Water Sedimentation Volume (mL) MicroscopySheared at % Fragmented Sample Unsheared 35 Volts Granules 7629-70 25  30 17.6 7629-70 STM 125 C. 26.5 30 18.3

The RVA profiles at pH 3.5 and 6.5 of inhibited starch made using oneheating cycle with sodium carbonate and citric acid in alcohol beforeand after desolventization are shown in FIG. 24.

FIG. 25 is a micrograph of starch cooked in 1% NaCl as prepared formeasuring the un-sheared sedimentation volumes. FIG. 26 is a micrographof starch cooked in 1% NaCl and then sheared using a blender as preparedfor measuring the sheared sedimentation volumes.

Native starch granules show birefringence or a typical Maltese crosswhen viewed in polarized light. The property of Maltese cross is broughtabout because the starch molecules are radially oriented within thegranule. When starch is heated in water, birefringence or Maltese crossin polarized light is lost by the end of starch gelatinization. FIG. 27shows that the Maltese cross property of starch granules is preservedwhen waxy starch have been processed using one heating cycle with sodiumcarbonate and citric acid in alcohol and desolventization, whichindicates that the starch is non-pregelatinized.

Sedimentation volumes are used to measure the extent of inhibition ofstarch in this study. A smaller un-sheared sedimentation volumeindicates less swelling of cooked starch granules and a higherinhibition. A smaller change of sheared sedimentation volumes comparedto un-sheared sedimentation volumes indicates a higher shear stability.This example shows that inhibited starch made using one heating cyclewith sodium carbonate and citric acid in alcohol is highly inhibited andshear-stable. The micrographs of cooked starch in 1% NaCl before (FIG.25) and after shearing (FIG. 26) using a blender at 25 Volts for 20 secshowed no significant fragmentation of cooked granules. Starch afterprocessing shows birefringence or a typical Maltese cross when viewed inpolarized light, which indicates that starch is non-pregelatinized.

1. A method for making an inhibited non-pregelatinized granular starch,wherein the method comprises heating a non-pregelatinized granularstarch in an alcoholic medium in the presence of at least one treatmentagent selected from the group consisting of bases and salts at atemperature of at least 35° C.
 2. (canceled)
 3. The method of claim 1,wherein the alcoholic medium is comprised of 0 to 20 weight percentwater.
 4. The method of claim 1, wherein the temperature is at least120° C.
 5. (canceled)
 6. (canceled)
 7. (canceled)
 8. The method of claim1, comprising an additional step of removing alcohol solvent from theinhibited non-pregelatinized granular starch.
 9. The method of claim 1,comprising an additional step of separating the inhibitednon-pregelatinized granular starch from the alcoholic medium and heatingthe separated inhibited non-pregelatinized granular starch.
 10. Themethod of claim 9, wherein the heating of the separated inhibitednon-pregelatinized granular starch is conducted at a temperature of atleast 120° C.
 11. The method of claim 1, comprising an additional stepof treating the inhibited non-pregelatinized granular starch with steam.12. (canceled)
 13. (canceled)
 14. (canceled)
 15. The method of claim 1,wherein the non-pregelatinized granular starch is in the form of aslurry in the alcoholic medium and the pH of the slurry is at least 6.16. The method of claim 1, wherein the at least one treatment agentincludes a base and the method comprises an additional step ofneutralizing the base in the inhibited non-pregelatinized granularstarch with an acid.
 17. (canceled)
 18. (canceled)
 19. (canceled) 20.The method of claim 16, comprising an additional step afterneutralization of heating the inhibited non-pregelatinized granularstarch in the alcoholic medium.
 21. (canceled)
 22. (canceled) 23.(canceled)
 24. The method of claim 1, wherein the at least one treatmentagent includes a carboxylic acid salt.
 25. The method of claim 1,wherein the at least one treatment agent includes a pulyuarboxyk addsalt.
 26. (canceled)
 27. The method of claim 1, wherein the at least onetreatment agent includes one or more sodium salts of citric acid. 28.The method of claim 1, wherein the alcoholic medium is basic.
 29. Themethod of claim 1, wherein the alcoholic medium is neutral.
 30. Themethod of claim 1, wherein the method comprises: a) heating thenon-pregelatinized granular starch in the alcoholic medium in thepresence of a base at a temperature of at least 35° C.; b) neutralizingthe base with an acid; c) separating the inhibited non-pregelatinizedgranular starch from the alcoholic medium; and d) removing alcoholsolvent from the inhibited non-pregelatinized granular starch byheating.
 31. The method of claim 1, wherein the method comprises: a)heating a slurry of the non-pregelatinized granular starch in an aqueousethanol medium in the presence of a base at a temperature of 120° C. to200° C.; b) neutralizing the base with an acid; c) separating theinhibited non-pregelatinized granular starch from the aqueous ethanolmedium; and d) contacting the separated inhibited non-pregelatinizedgranular starch with steam at a temperature of from 100° C. to 200° C.to remove residual ethanol.
 32. The method of claim 1, wherein themethod comprises: a) heating the non-pregelatinized granular starch inthe alcoholic medium in the presence of a base at a temperature of atleast 35° C.; b) neutralizing the base with an acid to provide aneutralized slurry; c) heating the neutralized slurry at a temperatureof at least 35° C.; d) separating the inhibited non-pregelatinizedgranular starch from the alcoholic medium; and e) removing alcoholsolvent from the inhibited non-pregelatinized granular starch byheating.
 33. A method for making an inhibited non-pregelatinizedgranular starch, wherein the method comprises: a) heating anon-pregelatinized granular starch in an alcoholic medium in thepresence of at least one carboxylic acid salt at a temperature of atleast 35° C.; b) separating the inhibited non-pregelatinized granularstarch from the alcoholic medium; and c) removing alcohol solvent fromthe inhibited non-pregelatinized granular starch by heating. 34.(canceled)
 35. (canceled)
 36. (canceled)
 37. (canceled)
 38. (canceled)39. (canceled)
 40. (canceled)
 41. (canceled)
 42. (canceled) 43.(canceled)
 44. (canceled)
 45. (canceled)
 46. (canceled)
 47. (canceled)48. (canceled)
 49. (canceled)
 50. (canceled)
 51. An inhibitednon-pregelatinized granular starch obtained in accordance with themethod of claim
 1. 52. An inhibited non-pregelatinized granular starchobtained in accordance with the method of claim
 30. 53. An inhibitednon-pregelatinized granular starch obtained in accordance with themethod of claim
 31. 54. An inhibited non-pregelatinized granular starchobtained in accordance with the method of claim
 32. 55. An inhibitednon-pregelatinized granular starch obtained in accordance with themethod of claim 33.